@Sina-Ranjkesh-zade said in Converting QByteArray to QString:
For "standard input" if you mean input arguments of the process, I got this error:
No, I meant standard input. That is , the python program reads from a terminal and accepts input just as if you typed it (except it is the Qt program sending that input). The Qt program can send a command to the python program, send the data it needs, and read the result (if there is one) back on the python program's standard output. Or you can used shared memory, or a socket, or files, or do whatever the python program is doing in the Qt program...